Clockwise
Example
Problem: Triangle ABC has vertices A(1, 3), B(4, 3), and C(4, 1). Describe the order in which you encounter the vertices when tracing the triangle clockwise starting from A.
Step 1: Plot the points. A is at the upper left, B is at the upper right, and C is at the lower right.
Step 2: Starting at A and moving clockwise (right first, since A is at the top-left), you reach B, then move down to C, then back up-left to A.
Answer: Tracing the triangle clockwise from A gives the order A → B → C → A.
Why It Matters
Clockwise and counterclockwise directions matter whenever you describe rotations in geometry. A 90° clockwise rotation produces a different image than a 90° counterclockwise rotation. Specifying the direction also matters in real-world contexts like tightening screws (clockwise) or reading angles in trigonometry.
Common Mistakes
Mistake: Confusing clockwise with counterclockwise when performing rotations on a coordinate plane.
Correction: Remember: clockwise goes in the same direction clock hands move (top → right → bottom → left). A 90° clockwise rotation about the origin maps the point (x,y) to (y,−x), while a 90° counterclockwise rotation maps it to (−y,x).
Related Terms
- Counterclockwise — The opposite direction of rotation
- Rotation — A transformation that turns a figure around a point
- Angle — Measured by the direction of rotation between rays
- Transformation — General term for moving or changing a figure